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STATUS: INCOMPATIBLE ⬌ MATRIX CORRELATION INDEX

Can you keep Fancy Goldfish and Harlequin Rasbora together?

Algorithmically generated environmental and behavioral compatibility report.

Fancy GoldfishCarassius auratus
mid Layerpeaceful
incompatible
Harlequin RasboraTrigonostigma heteromorpha
mid Layerpeaceful
INCOMPATIBLE

Algorithmic Assessment

Water acidity (pH) parameters clash. Fancy Goldfish prefers a pH of 7-8, while Harlequin Rasbora requires a pH of 6-6.8. There is no overlapping safe pH range.

Scientific Parameter Comparison

Cross-reference water chemistry, temperature range envelopes, and physical dimensions of Fancy Goldfish and Harlequin Rasbora.

Parameter MetricFancy GoldfishHarlequin RasboraCalculated Overlap
Temperature Range65°F – 75°F73°F – 80°F73°F – 75°F
pH Chemistry7.0 – 8.06.0 – 6.8No Overlap (Mismatch: 0.2)
Min. Tank Capacity30 Gallons10 Gallons30 Gallons (Minimum)
Aquatic Strata ZonemidmidShared Zone (Layer Conflict)
Adult Size (Max)6.0" (15 cm)1.8" (4 cm)Ratio: 1 : 3.4

⚠ Physiological Mismatch Report

Our stocking engine calculations indicate that putting these two species in the same tank causes acute physiological strain. Below are the calculated parameters that violate safe cohabitation ranges:

Acidity/pH Gap0.2 pH difference

Fancy Goldfish thrives in pH 7-8, while Harlequin Rasbora needs pH 6-6.8.

Predation Threat MetricsSize Ratio: 3.4 : 1

Larger predators typically consume tankmates that fit into their mouths. Keeping a 6" species with a 1.75" species is dangerous.

⚔️ Do Fancy Goldfish and Harlequin Rasbora Fight?

Environmental or structural requirements between these species clash too heavily to allow cohabitation. Water acidity (pH) parameters clash. Fancy Goldfish prefers a pH of 7-8, while Harlequin Rasbora requires a pH of 6-6.8. There is no overlapping safe pH range.

🍽️ Swimming Layers & Feeding Competition

To satisfy their dietary requirements, offer a varied feeding schedule. Sinking pellets or wafers are ideal for bottom dwellers, while floating flakes or micro-granules support mid and top dwellers. Both species reside in the mid layer. Feeding them simultaneously in different corners of the tank is highly recommended to distribute food and prevent any resource competition in their shared vertical zone.

📏 Size Difference & Predation Threat

There is a moderate size difference. The Fancy Goldfish (6.0 inches) is noticeably larger than the Harlequin Rasbora (1.8 inches). While not an immediate predation threat under normal circumstances, ensure the smaller specimens are not small enough to be eaten and have plenty of shelter.

Safe Tankmate Alternatives for Fancy Goldfish

Since the pairing between Fancy Goldfish and Harlequin Rasbora is flagged as incompatible, here are 3 peaceful community tankmates that share a flawless compatibility profile with Fancy Goldfish and match similar water parameters:

Scientific NameCarassius auratus
Min Tank Capacity30G
Aggressionpeaceful
Temp Envelope65°F - 75°F
pH Chemistry7.0 - 8.0
Scientific NameTrigonostigma heteromorpha
Min Tank Capacity10G
Aggressionpeaceful
Temp Envelope73°F - 80°F
pH Chemistry6.0 - 6.8

Chemistry & Habitat Analysis

Temp Envelope
73°F - 75°F
Shared temperature bounds.
pH Chemistry
No Overlap
Acidity requirements clash.
Combined Min Tank
30 Gallons
Lowest acceptable volume.

Frequently Asked Questions: Fancy Goldfish & Harlequin Rasbora Compatibility

Are Fancy Goldfish and Harlequin Rasbora good tank mates?

Water acidity (pH) parameters clash. Fancy Goldfish prefers a pH of 7-8, while Harlequin Rasbora requires a pH of 6-6.8. There is no overlapping safe pH range.

Can you put Fancy Goldfish and Harlequin Rasbora in the same tank together?

Environmental or structural requirements between these species clash too heavily to allow cohabitation. Water acidity (pH) parameters clash. Fancy Goldfish prefers a pH of 7-8, while Harlequin Rasbora requires a pH of 6-6.8. There is no overlapping safe pH range.

What water temperature and pH parameters do Fancy Goldfish and Harlequin Rasbora need?

Both species require compatible parameters. Fancy Goldfish needs a temperature of 65°F to 75°F and a pH of 7.0 to 8.0. Meanwhile, Harlequin Rasbora needs a temperature of 73°F to 80°F and a pH of 6.0 to 6.8. Shared overlap range: 73°F–75°F temperature and No safe pH overlap overlap.

What is the minimum combined tank volume required to house Fancy Goldfish and Harlequin Rasbora?

To successfully house both species together, the minimum baseline capacity is 30 gallons. Because both Fancy Goldfish and Harlequin Rasbora are peaceful community species, no extra territorial buffer volume is required.